import java.util.List;
import java.util.ArrayList;

public class TomAccumulator implements StringAccumulator {
	
	private final List<CharSequence> strings;
	private final boolean lazy;
	private int length;
	
	public TomAccumulator(boolean lazy) {
		strings = new ArrayList<CharSequence>();
		this.lazy = lazy;
		length = 0;
	}
	
	public TomAccumulator() {
		this(false);
	}
	
	public void accumulate(Object obj) {
		if (lazy && obj instanceof CharSequence) accumulate((CharSequence)obj);
		else accumulate(obj.toString());
	}
	
	public void accumulate(String str) {
		accumulate((CharSequence)str);
	}
	
	private void accumulate(CharSequence s) {
		strings.add(s);
		length += s.length();
	}
	
	public String toString() {
		StringBuilder sb = new StringBuilder(length);
		for (CharSequence s: strings) sb.append(s);
		return sb.toString();
	}
	
}